A geographical location of a user equipment is calculated by basically measuring a delay time of signals transmitted from a plurality of cells. Accordingly, in order to measure a location of a user equipment, at least three or more signals are required. Based on this, various methods for calculating a location of a user equipment are provided. It is general that an observed time difference of arrival (OTDOA) scheme is mainly used.
FIG. 1 is a conceptual view illustrating an OTDOA scheme for measuring a location of a user equipment.
Referring to FIG. 1, the OTDOA scheme is to measure a location of a user equipment by using the difference in timing of signals transmitted from respective cells to the user equipment. The user equipment measures a delay time of each signal received from each cell and reports the measured delay times to a serving cell or an anchor cell. The serving cell measures a location of the corresponding user equipment by using the reported delay times.
Meanwhile, in order to provide a communication service of high quality, the need of a location measurement scheme for determining a location of a user equipment within a network and/or locations of entities related to the user equipment more exactly has been increased. In this respect, an advanced method for determining a location while minimizing an effect on a structure of an existing radio frame should be provided.